1. Field of the Invention
The present invention relates to a device for forming a variable-shape mold surface. It is within the scope of the present invention to digitally adjust the configuration of the mold surface through a computer system.
2. Brief Description of the Prior Art
In the industry of plastic and foam molding as well as in the foundries, models are currently used to fabricate molds. When intricate shapes are involved without requiring a great dimensional precision, these models are often made by craftsmen. Such models are costly and the delivery delay is of some weeks.
The manufacture of these models can also be automated by means of digitally controlled machining equipments. The drawback is that these equipments require complex and lengthy programs often overstepping their memory capacity. Also, machining by means of these equipments is very time-consuming. Finally, purchase and operation of such equipments involve high costs.
Moreover, in a research and development project, many versions of the same model are often required. Craft or digitally controlled manufacture of models are both time-consuming and costly.
Canadian patent N.sup.0 938,173 granted to the Ford Motor Company of Canada, Limited on Dec. 11, 1973 discloses a solution to the above problem. More specifically, this document describes a method of constructing mold surfaces by means of a bundle of laterally adjacent hexagonal rods. In accordance with this method, the hexagonal rods are precut at given lengths and angles, and are thereafter assembled together to form the bundle. Obviously, each rod must be placed in a predetermined position in the bundle to form the desired mold surface shape. The drawback of this prior art method is that the configuration of the mold surface is permanent and cannot be modified.
U.S. Pat. No. 2,968,838 (Hicks) issued on Jan. 24, 1961 also proposes the use of a bundle of laterally adjacent rods to imprint on a generally planar surface an image having a tridimensional appearance. These rods have a square cross section. They are slid longitudinally to enable machining thereof at one end. The shaped ends are then replaced in coplanar relationship to form a planar die. The rods are then assembled permanently into a bundle. Again, the disadvantage is that the pattern of the die is permanent.